ACT Science : Biology

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #601 : Biology

In the 17th century, scientists were just beginning to understand the circulatory system of the heart. The two following viewpoints are the two most popular theories of the day.

Scientist I The heart pumps blood through arteries and veins but the two systems are separate. They are similar, just as the senses of smell and taste are when observing food, but ultimately they are two separate systems which perform separate functions. Hot blood flows from the heart, through the arteries, and to the organs which consume the blood much as a human would consume nourishment to survive. Venous blood originates in the liver and follows the veins to the organs where it is similarly consumed.

Scientist II The arteries and veins are two parts of one system. Blood flows from the heart, around the body, and back into the heart through the veins like two sets of one way streets. The idea of two systems, each pumping blood to the organs is unreasonable. If the heart can pump 6 oz of blood per minute, then the liver would have to produce 540 pounds of blood per day. A simple measurement of a human’s weight shows how unlikely that solution is. The single circulatory system is far superior as it explains the function of the heart, the arteries, and the veins clearly.

About which point do the two theories differ?

Possible Answers:

The amount of blood in the human body.

The purpose of the liver in the digestive system.

The purpose of veins.

The amount of blood in the heart.

Correct answer:

The purpose of veins.

Explanation:

Both scientists agree that blood from the heart flows through the arteries. However, Scientist I believes that liver blood flows through the veins whereas Scientist II believes that the same heart blood travels back to the heart through the veins.

Example Question #602 : Biology

In the 17th century, scientists were just beginning to understand the circulatory system of the heart. The two following viewpoints are the two most popular theories of the day.

Scientist I The heart pumps blood through arteries and veins but the two systems are separate. They are similar, just as the senses of smell and taste are when observing food, but ultimately they are two separate systems which perform separate functions. Hot blood flows from the heart, through the arteries, and to the organs which consume the blood much as a human would consume nourishment to survive. Venous blood originates in the liver and follows the veins to the organs where it is similarly consumed.

Scientist II The arteries and veins are two parts of one system. Blood flows from the heart, around the body, and back into the heart through the veins like two sets of one way streets. The idea of two systems, each pumping blood to the organs is unreasonable. If the heart can pump 6 oz of blood per minute, then the liver would have to produce 540 pounds of blood per day. A simple measurement of a human’s weight shows how unlikely that solution is. The single circulatory system is far superior as it explains the function of the heart, the arteries, and the veins clearly.

According to Scientist II, what is the direction of blood?

Possible Answers:

From the heart, through the veins and the arteries, into the organs where it is consumed.

From the heart, through the arteries, through the veins, back into the heart.

From the heart, through the arteries, into the lungs, through the veins, into the liver.

From the liver, through the veins, into the heart, through the arteries.

Correct answer:

From the heart, through the arteries, through the veins, back into the heart.

Explanation:

Scientist II believes that blood moves in a giant circle. It goes from the heart, through the arteries, into the veins, and then back into the heart.

Example Question #603 : Biology

In the 17th century, scientists were just beginning to understand the circulatory system of the heart. The two following viewpoints are the two most popular theories of the day.

Scientist I The heart pumps blood through arteries and veins but the two systems are separate. They are similar, just as the senses of smell and taste are when observing food, but ultimately they are two separate systems which perform separate functions. Hot blood flows from the heart, through the arteries, and to the organs which consume the blood much as a human would consume nourishment to survive. Venous blood originates in the liver and follows the veins to the organs where it is similarly consumed.

Scientist II The arteries and veins are two parts of one system. Blood flows from the heart, around the body, and back into the heart through the veins like two sets of one way streets. The idea of two systems, each pumping blood to the organs is unreasonable. If the heart can pump 6 oz of blood per minute, then the liver would have to produce 540 pounds of blood per day. A simple measurement of a human’s weight shows how unlikely that solution is. The single circulatory system is far superior as it explains the function of the heart, the arteries, and the veins clearly.

According to Scientist II, which of the following is NOT true?

Possible Answers:

The liver pumps blood.

The veins bring blood back to the heart.

Blood moves through the arteries in one direction.

The heart pumps blood.

Correct answer:

The liver pumps blood.

Explanation:

Scientist II believes that the heart alone is responsible for the creation of blood in the human body.

Example Question #604 : Biology

In the 17th century, scientists were just beginning to understand the circulatory system of the heart. The two following viewpoints are the two most popular theories of the day.

Scientist I The heart pumps blood through arteries and veins but the two systems are separate. They are similar, just as the senses of smell and taste are when observing food, but ultimately they are two separate systems which perform separate functions. Hot blood flows from the heart, through the arteries, and to the organs which consume the blood much as a human would consume nourishment to survive. Venous blood originates in the liver and follows the veins to the organs where it is similarly consumed.

Scientist II The arteries and veins are two parts of one system. Blood flows from the heart, around the body, and back into the heart through the veins like two sets of one way streets. The idea of two systems, each pumping blood to the organs is unreasonable. If the heart can pump 6 oz of blood per minute, then the liver would have to produce 540 pounds of blood per day. A simple measurement of a human’s weight shows how unlikely that solution is. The single circulatory system is far superior as it explains the function of the heart, the arteries, and the veins clearly.

If it were discovered that the heart both pumped blood out and sucked blood back in, which theory would this support?

Possible Answers:

Scientist II

Scientist I

Both theories

Neither theory

Correct answer:

Scientist II

Explanation:

Scientist II believes blood returns to the heart, whereas Scientist I believes that blood only leaves that heart.

Example Question #605 : Biology

In the 17th century, scientists were just beginning to understand the circulatory system of the heart. The two following viewpoints are the two most popular theories of the day.

Scientist I The heart pumps blood through arteries and veins but the two systems are separate. They are similar, just as the senses of smell and taste are when observing food, but ultimately they are two separate systems which perform separate functions. Hot blood flows from the heart, through the arteries, and to the organs which consume the blood much as a human would consume nourishment to survive. Venous blood originates in the liver and follows the veins to the organs where it is similarly consumed.

Scientist II The arteries and veins are two parts of one system. Blood flows from the heart, around the body, and back into the heart through the veins like two sets of one way streets. The idea of two systems, each pumping blood to the organs is unreasonable. If the heart can pump 6 oz of blood per minute, then the liver would have to produce 540 pounds of blood per day. A simple measurement of a human’s weight shows how unlikely that solution is. The single circulatory system is far superior as it explains the function of the heart, the arteries, and the veins clearly.

Which of the following would be a good title for Scientist I's argument?

Possible Answers:

"The Smell and Taste of Blood"

"The Two Organs That Make Blood"

"Why the Heart is Irrelevant in the Circulatory System"

"The One-Way Circulatory System"

Correct answer:

"The Two Organs That Make Blood"

Explanation:

Scientist I believes that blood is created by two organs and spends his paragraph defending this theory. This is the only option that succinctly captures that.

Example Question #606 : Biology

Genes are hereditary units that are responsible for the phenotypes of an organism. Genes are the directions for the body. Genetic change exists when genes are altered from their previous form. Genes are made up of DNA, or deoxyribonucleic acid. DNA is made up of four bases- adenine, guanine, cytosine, and thymine. Genetic change can result from a variety of factors. Both scientists mentioned below agree on this basic information about genes. However, the scientists do not agree on the primary driving force behind genetic change.

 

Scientist 1

A mutation is a permanent change in the sequence of the DNA of a gene. There are several types of mutations—point mutations, silent mutations, frame mutations, and nonsense mutations. Mutations are very important because proteins are synthesized by reading the DNA sequence. If the DNA sequence is changed, the proteins transcribed from the DNA will be different proteins. Mutations directly and substantially change the genes by changing the sequence of the four bases. Therefore, mutations are the main factor when looking at genetic change.

 

 

Scientist 2 

Sexual reproduction is the biggest contributor to genetic change. New combinations of genes are created with every random union of a sperm and egg. During division of the sex cells, or meiosis, crossing over can occur. Crossing over describes the situation when the genes from one parent’s chromosome are traded with genes from the other parent’s chromosome. This results in new combinations of genes. Lastly, a phenomenon called independent assortment results from sexual reproduction. Independent assortment is the random assortment of chromosomes during reproduction. Therefore, by its random nature, sexual reproduction is the largest contributor to genetic change.

What information would weaken the viewpoint of Scientist 1?

Possible Answers:

The majority of mutations are silent mutations, which result in a nucleotide change but not a change in the protein.  

Mutations are extremely common. 

Sexual reproduction does not result in genetic variation. 

Most mutations are not detectable. 

Genes are not easily changed by outside factors, and variation only results from mutations. 

Correct answer:

The majority of mutations are silent mutations, which result in a nucleotide change but not a change in the protein.  

Explanation:

If the majority of mutations were silent and did not affect the protein read from the DNA, one could argue the impact of the mutation would be greatly reduced. 

Example Question #607 : Biology

Genes are hereditary units that are responsible for the phenotypes of an organism. Genes are the directions for the body. Genetic change exists when genes are altered from their previous form. Genes are made up of DNA, or deoxyribonucleic acid. DNA is made up of four bases- adenine, guanine, cytosine, and thymine. Genetic change can result from a variety of factors. Both scientists mentioned below agree on this basic information about genes. However, the scientists do not agree on the primary driving force behind genetic change.

 

Scientist 1

A mutation is a permanent change in the sequence of the DNA of a gene. There are several types of mutations—point mutations, silent mutations, frame mutations, and nonsense mutations. Mutations are very important because proteins are synthesized by reading the DNA sequence. If the DNA sequence is changed, the proteins transcribed from the DNA will be different proteins. Mutations directly and substantially change the genes by changing the sequence of the four bases. Therefore, mutations are the main factor when looking at genetic change.

 

 

Scientist 2 

Sexual reproduction is the biggest contributor to genetic change. New combinations of genes are created with every random union of a sperm and egg. During division of the sex cells, or meiosis, crossing over can occur. Crossing over describes the situation when the genes from one parent’s chromosome are traded with genes from the other parent’s chromosome. This results in new combinations of genes. Lastly, a phenomenon called independent assortment results from sexual reproduction. Independent assortment is the random assortment of chromosomes during reproduction. Therefore, by its random nature, sexual reproduction is the largest contributor to genetic change.

Scientist 2 believes sexual reproduction is the biggest contributor to change because it involves:

Possible Answers:

crossing over

union of egg and sperm

independent assortment

none of the options listed 

All of the options listed 

Correct answer:

All of the options listed 

Explanation:

Scientist 2 specifically discusses crossing over, independent assortment, and sperm egg union as the three reasons sexual reproduction result in genetic change. 

Example Question #608 : Biology

Genes are hereditary units that are responsible for the phenotypes of an organism. Genes are the directions for the body. Genetic change exists when genes are altered from their previous form. Genes are made up of DNA, or deoxyribonucleic acid. DNA is made up of four bases- adenine, guanine, cytosine, and thymine. Genetic change can result from a variety of factors. Both scientists mentioned below agree on this basic information about genes. However, the scientists do not agree on the primary driving force behind genetic change.

 

Scientist 1

A mutation is a permanent change in the sequence of the DNA of a gene. There are several types of mutations—point mutations, silent mutations, frame mutations, and nonsense mutations. Mutations are very important because proteins are synthesized by reading the DNA sequence. If the DNA sequence is changed, the proteins transcribed from the DNA will be different proteins. Mutations directly and substantially change the genes by changing the sequence of the four bases. Therefore, mutations are the main factor when looking at genetic change.

 

 

Scientist 2 

Sexual reproduction is the biggest contributor to genetic change. New combinations of genes are created with every random union of a sperm and egg. During division of the sex cells, or meiosis, crossing over can occur. Crossing over describes the situation when the genes from one parent’s chromosome are traded with genes from the other parent’s chromosome. This results in new combinations of genes. Lastly, a phenomenon called independent assortment results from sexual reproduction. Independent assortment is the random assortment of chromosomes during reproduction. Therefore, by its random nature, sexual reproduction is the largest contributor to genetic change.

The viewpoints of Scientist 1 and Scientist 2 both support what theory? 

Possible Answers:

Mutations during crossing over are the biggest contributor to genetic change. 

Genetic change is the variation of genes from one generation to another. 

Genetic change cannot exist without a changing environment. 

Sexual reproduction results in genetic change. 

Mutations are the biggest contributor to genetic change. 

Correct answer:

Genetic change is the variation of genes from one generation to another. 

Explanation:

The first paragraph discusses genetic change and describes it as the variation of genes from one generation to another. It goes on to say both scientists "agree on this basic information about genes."

Example Question #609 : Biology

Genes are hereditary units that are responsible for the phenotypes of an organism. Genes are the directions for the body. Genetic change exists when genes are altered from their previous form. Genes are made up of DNA, or deoxyribonucleic acid. DNA is made up of four bases- adenine, guanine, cytosine, and thymine. Genetic change can result from a variety of factors. Both scientists mentioned below agree on this basic information about genes. However, the scientists do not agree on the primary driving force behind genetic change.

 

Scientist 1

A mutation is a permanent change in the sequence of the DNA of a gene. There are several types of mutations—point mutations, silent mutations, frame mutations, and nonsense mutations. Mutations are very important because proteins are synthesized by reading the DNA sequence. If the DNA sequence is changed, the proteins transcribed from the DNA will be different proteins. Mutations directly and substantially change the genes by changing the sequence of the four bases. Therefore, mutations are the main factor when looking at genetic change.

 

 

Scientist 2 

Sexual reproduction is the biggest contributor to genetic change. New combinations of genes are created with every random union of a sperm and egg. During division of the sex cells, or meiosis, crossing over can occur. Crossing over describes the situation when the genes from one parent’s chromosome are traded with genes from the other parent’s chromosome. This results in new combinations of genes. Lastly, a phenomenon called independent assortment results from sexual reproduction. Independent assortment is the random assortment of chromosomes during reproduction. Therefore, by its random nature, sexual reproduction is the largest contributor to genetic change.

Which of the following best states the belief of Scientist 1? 

Possible Answers:

If a DNA sequence is changed, the proteins transcribed from the DNA will be different proteins. 

Because sexual selection is so random, it is the driving factor for genetic change. 

Mutations result in the change of the base pairs on DNA, therefore they are the primary contributor to genetic change. 

Genetic change can result from a variety of factors.

Genetic change exists when genes are altered from their previous form. 

Correct answer:

Mutations result in the change of the base pairs on DNA, therefore they are the primary contributor to genetic change. 

Explanation:

The main belief of Scientist 1 is that mutations are the most important contributor to genetic change. The last sentence in the parapgraph states that "mutations are the main factor when looking at genetic change."

 

Example Question #610 : Biology

Genes are hereditary units that are responsible for the phenotypes of an organism. Genes are the directions for the body. Genetic change exists when genes are altered from their previous form. Genes are made up of DNA, or deoxyribonucleic acid. DNA is made up of four bases- adenine, guanine, cytosine, and thymine. Genetic change can result from a variety of factors. Both scientists mentioned below agree on this basic information about genes. However, the scientists do not agree on the primary driving force behind genetic change.

 

Scientist 1

A mutation is a permanent change in the sequence of the DNA of a gene. There are several types of mutations—point mutations, silent mutations, frame mutations, and nonsense mutations. Mutations are very important because proteins are synthesized by reading the DNA sequence. If the DNA sequence is changed, the proteins transcribed from the DNA will be different proteins. Mutations directly and substantially change the genes by changing the sequence of the four bases. Therefore, mutations are the main factor when looking at genetic change.

 

 

Scientist 2 

Sexual reproduction is the biggest contributor to genetic change. New combinations of genes are created with every random union of a sperm and egg. During division of the sex cells, or meiosis, crossing over can occur. Crossing over describes the situation when the genes from one parent’s chromosome are traded with genes from the other parent’s chromosome. This results in new combinations of genes. Lastly, a phenomenon called independent assortment results from sexual reproduction. Independent assortment is the random assortment of chromosomes during reproduction. Therefore, by its random nature, sexual reproduction is the largest contributor to genetic change.

You could infer Scientist 2 would most likely agree with what statement?

Possible Answers:

Mutations do not contribute at all to genetic change. 

Random environmental events contribute greatly to genetic change.

Scientist 2 would agree with all of these statements. 

Survival of the fittest results in genetic change. 

Scientist 2 would not agree with any of these statements.

Correct answer:

Random environmental events contribute greatly to genetic change.

Explanation:

The last sentence in the argument by Scientist 2 concludes that "by its random nature, sexual reproduction is the largest contributor to genetic change." Therefore, one could conclude that because Scientist 2 values the randomness of sexual reproduction, Scientist 2 would agree with another random event being a large contributor to genetic change.

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